JP2658503B2 - Reciprocating painting method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a reciprocating coating method that can be carried out in a coating factory for an automobile body.

(Prior Art) An automobile body will be described as an example of an object to be coated. The coating of the vehicle body is performed while the coating gun is reciprocating in a direction perpendicular to the longitudinal direction (moving direction) of the object to be coated (car body) moving at a constant speed by the conveyor. Is common. In this case, usually, approximately three coating guns arranged side by side are simultaneously reciprocated to perform uniform coating on an object having a lateral width. By the way, when the object to be coated is an automobile body as described above, the width of the engine hood, the roof, and the trunk hood usually differ from each other. Needs to be changed. This is to prevent so-called overspray, to prevent useless use of paint, and to prevent air pollution.

This will be described with reference to the drawings. In FIG. 3, reference numeral 1 denotes an object to be coated, 2 denotes a paint sprayed toward the object to be coated 1, 3 denotes a coating gun, 4 denotes an on / off valve of the paint 2, 5 denotes a paint tube, 6 denotes an on / off valve 4. A sequencer 7 for setting and controlling the number of pulses for opening and closing the control unit 7 is a setting device for adjusting the position of the coating gun 3 to a desired position. When the object to be coated 1 is coated in such a system, when the number of the coating guns 3 is one, the coating gun 3 has a locus indicated by reference numeral 8 in FIG.
Will be moved. For example, when painting the workpiece 1 moving in the direction of arrow A, the right end 1a of the workpiece 1
The coating gun 3 moving left from the side is the left end 1b of the work 1
, Then move from left to right.
When returning to the right end 1a of the work 1 again, the left end 1b
Move towards. By repeating this, a painting operation is performed.

The above is the operation in the case where the number of the coating guns 3 is one for the object 1 to be coated. When the number of the coating guns 3 is three, the operation becomes as shown in FIG. In this case, the operation is basically the same as that in FIG. 4, but since the number of the painting guns 3 is three, the moving stroke is small, and the object 1 is painted in three parts. become.

Moving the coating gun 3 by the reciprocating motion in this way means that the coating gun 3 has advanced a predetermined stroke in a certain direction (if there are three coating guns, the coating guns 3 on both sides reach predetermined positions. Stop) and then proceed in the opposite direction repeatedly. At the end of the stroke, the moving speed of the coating gun 3 becomes small (slow) near the end because the moving direction is changed. Then, control is performed such that the discharge of the paint 2 from the paint gun 3 is stopped at the end of the stroke, and the paint 2 is discharged again when it starts moving in the opposite direction.

Conventionally, in controlling the paint cutting as described above, the on / off valve of the paint is operated by an air switching action of a limit switch or a proximity switch attached to a crank portion. The operation timing of the ON / OFF valve at this time is set in advance by using a pulse transmitter provided so that the air switching operation is performed at a certain pulse after the limit switch or the proximity switch of the crank portion is operated. .

(Problems to be Solved by the Invention) By the way, when controlling the ON / OFF valve of the paint in this way, the operation of the ON / OFF valve is delayed due to the diameter, length, pressure, etc. of the operating air hose, and the The delay time is not constant. For this reason, it is difficult to grasp the paint on / off position (reset position in FIGS. 4 and 5), and there is a problem that much time is required for the adjustment. In addition, due to poor setting of the ON / OFF timing of the paint or fluctuation of the ON / OFF position, unevenness of the ON / OFF timing of the paint occurs, resulting in poor coating film thickness distribution,
In addition, uneven coating may occur, resulting in poor quality.

The present invention has been made for the purpose of solving such a problem of the conventional reciprocating coating method.

(Means for Solving the Problems) The present invention provides, as a means for solving the above-mentioned problems, a reciprocal coating method for performing coating while reciprocating a coating gun 3 with respect to a moving workpiece 1. The action of the cam for determining the reciprocating turn position of the gun 3 is performed by an electric pulse signal, and the sensor (for example, the pressure sensor 9) detects the actual on / off position of the paint. The actual on / off position is compared with an appropriate on / off position set in advance (arithmetic unit 11), and when there is a deviation, the generation time of the electric pulse signal is eliminated from the deviation value. A reciprocal coating method characterized by automatically setting (by the computing unit 11) to a point in time is obtained.

(Action) According to the method of the present invention having such a configuration, the movement of the coating gun 3 is periodically checked, and the pulse generation time is corrected as necessary, so that the stroke of the coating gun 3 is always predetermined. It can be maintained within the range.

(Example) Next, an example of the method of the present invention will be described. In FIG. 1, 1 is an object to be coated, 2 is a paint sprayed toward the object to be coated 1, 3 is a coating gun, 4 is an on / off valve of the paint 2,
5, a paint tube; 6, a sequencer for setting and controlling the number of pulses for opening and closing the on / off valve 4;
Is a setting device for adjusting the position of the camera to a desired position. The basic circuit so far is the same as that of FIG. Third on circuit
What is different from the one in the figure is that a pressure sensor 9 is interposed between the coating gun 3 and the on / off valve 4, an amplifier 10 for amplifying an output signal of the pressure sensor 9, and a calculator 11 for measuring and calculating. Is provided, and the output side of the arithmetic unit 11 is connected to the setting unit 7.

The pressure sensor 9 is for detecting the actual ON / OFF operation of the paint, and detects this based on the pressure of the flowing paint. It may be. Sequencer 6
Is for setting and controlling the number of pulses for opening and closing the on / off valve 4, and is performed by an electric pulse signal of a pulse oscillator. The output signal of the sequencer 6 is applied to the on / off valve 4 to control the on / off timing.

FIG. 2 shows the pressure waveform by the actual on / off operation of the paint generated by the above-described pressure sensor 9 and the output waveform of the above-mentioned limit switch or proximity switch by a temporal change on the horizontal axis of the graph. Things. In this figure, time 0 when the proximity switch waveform rises means that the coating gun 3 is at the end of the object 1, that is, at the reset position, and 1 from this point until time T ₀ is reset. Cycle. The paint on is indicated by T ₁ , off by T ₂ , on again by T ₃ , and off on this again by T ₄ , and the actual on and off times are indicated by dashes such as T ′. If the desired on / off times are expressed without dashes such as T, the time relationship is as shown in FIG.

In the system path of FIG. 1, the actual paint on, than the off time T '1 _{through T' 4} caused by the number of pulses is C '1 _{-C' 4,} the desired this ON, OFF time T ₁ ~ T ₄
In order to correct this, the times T _{1 to} T ₄ are input to the arithmetic unit 11, where they are calculated, and as a result, the true pulse numbers C _{1 to} C ₄ are obtained, and these are input to the sequencer 6. As a result, the on and off positions are automatically corrected. The content of the operation performed by the arithmetic unit 11 is expressed by the following equation under the condition of 1 ≦ n ≦ 3.

When controlled in this manner, the reciprocating motion pattern of the coating gun 3 with respect to the workpiece 1 is as shown in FIGS. 6 and 7. When these are compared with those shown in FIGS. 4 and 5 showing the conventional reciprocating motion patterns, it can be seen that the stroke in the portion beyond the reset position is reduced.

(Effects of the Invention) As described above, in the reciprocating coating method, the present invention is configured such that the action of the cam for determining the reciprocating turn position of the coating gun is performed by an electric pulse signal, and the actual operation is performed by a pressure sensor or the like. The on / off position of the paint to be performed is detected, and the detected actual on / off position is compared with an appropriate on / off position set in advance. Since the reciprocating coating method is characterized in that the point of occurrence is automatically set so as to be a point at which the deviation value is eliminated, the following effects can be obtained.

Conventionally, a great deal of time has been spent adjusting the on and off positions of the on and off valves, but the time can be significantly reduced.

In the conventional timing setting mechanism, since it was difficult to set the position with high accuracy, the reciprocating turn-back position of the coating gun was set to be large in view of safety. Waste of paint is eliminated, and air pollution can be prevented and costs can be reduced.

In connection with the above overspray prevention function, paint can be prevented from adhering to the non-painted portion of the object to be coated, so that a coating film thickness distribution defect or even a coating unevenness occurs.
It does not cause poor quality.

[Brief description of the drawings]

FIG. 1 is a system diagram showing a coating system for realizing the method of the present invention,
FIG. 2 is a graph showing the operation timing of that of FIG. 1,
FIG. 3 is a system diagram showing a conventional coating system, FIGS. 4 and 5 are explanatory diagrams showing reciprocal patterns in FIG. 3, and FIGS. 6 and 7 are reciprocal patterns in FIG. FIG. 1 ... substrate 2 ... paint 3 ... paint gun 4 ... on / off valve 6 ... sequencer 7 ... setting device 9 ... pressure sensor 10 ... amplifier 11 ... computing device

Claims (1)

(57) [Claims] In a reciprocal coating method for performing coating while moving a coating gun on a moving object to be coated, a cam for determining a reciprocating turn position of the coating gun is performed by an electric pulse signal. At the same time, the sensor detects the actual on / off position of the paint, the detected actual on / off position,
A reciprocating processor characterized by comparing with an appropriate on / off position set in advance and, when there is a deviation, automatically setting the generation point of the electric pulse signal to the point when the deviation value is eliminated. Painting method.